I tried to do multiple plants in a pot so that I could maximize the amount of females I would end up with. After advice and observation, I decided (before they sexed) to take my chances and kill them off so there was only 1 plant per pot. Now that they are in flowering, I am very glad I did it because about a week after I weeded them out, they really started to take off. Out of around 13 plants I ended up with 5 females, which is more then enough.

When you remove one, you can really tell how the roots intertwine. That said, I think the biggest problem is that...if one of the plants develops its own problem, then you cant specifically treat it because yo have to keep the other plant in mind. I have also seen some setups where they used planter boxes, all the roots intertwined, and they thrived. Tranoble has one in Growroom Setup. He says the roots get so intertwined he has to cut them up to remove them when its over. But they flourish.